4 Strong Cosmic Censorship

The idea of cosmic censorship goes back to the work of Roger Penrose; see [62] (reprinted in [64]) and [63].
It comes in two forms: weak and strong. The weak cosmic-censorship conjecture is concerned with
isolated systems and essentially states that, generically, singularities should not be visible to an
observer at infinity; see [90] for a more precise and extensive discussion. The strong cosmic
censorship conjecture is a statement concerning the deterministic nature of the general theory of
relativity. This is the form we are interested in here, and we shall phrase it in terms of initial
data. Consequently, we need to formulate the initial value (or Cauchy) problem for Einstein’s
equations.